PROBLEM #1 詹弘彥

Fon老師 ∼

我的作業一是以email的方式傳給老師的，但為了求完整性，所以還是將之前寫的作業一給放上來。

P.S.~這次作業一『我沒有遲交喔』

謝謝老師啦！！ ^_^

1. The unit of POWER can be expressed as W, kW, hp, etc. Their equivalent expressions are J/s, kJ/s, in which J is joule to represent work and 1 J=0.101972kgm (You may find unit conversion table at http://www.digitaldutch.com/unitconverter/). Now, by using such relations find out the following condition when a farm tractor pulls a farm equipment working on the field at 20m/min. Suppose the draft force is meaured as 200kgf. Find out the power of the tractor.
   MATLAB CODE

>> F=200;%拉力（kg）

>> S=20;%移動距離（m）

>> T=60;%時間（sec）

>> A=9.81;%1kgm/s=9.81w

>> W=F*(S/T)*A; %W(w)

>> W=654

W =654(w)

2. A circuit with three resistors rated 1, 20,200 ohms in series is connected to a voltage source of 110V. Find the line current and power consumption.
   >> a=1;b=20;c=200;%電阻器

>> v=110;%電壓

>> r=a+b+c;%電阻串連

>> i=v/r;%i=電流(A)

>> p=i*v;%p=功率

>> i

i =0.4977

>> p

p =54.7511

3. Calculate the area of a trangle with three sides in 650cm, 428cm, 282cm, repectively.
   >> a=650;b=428;c=282;%三角形三邊邊長(cm)

>> s=(a+b+c)/2;

>> area=(s*(s-a)*(s-b)*(s-c))^0.5;%海龍公式

>> area

area =4.5233e+004

4. A hog house was designed the way that heat dissipations from lighting & equipment 25,000BTU/hr, heat flux through wall & cellings 52,000BTU/hr , heat flux through aerations 84,300BTU/hr. Suppose each hog will dissipate 600BTU/hr, how many hogs this house can raise?

>> wall=52000;fan=84300;%散出的熱量

>> input=25000;%照明與設備產生的熱量

>> pig=600;%豬產生的熱量

>> allpig=(wall+fan-input)/pig;%最多的豬量

>> allpig

allpig =185.5000

所以最多只能養185隻

5. The flow rate of a rectangular water gate can be calculated from the following formula: Q=3.33x[L-0.2H]^(3/2), in which L: width of gate in ft, H:water head in ft and Q: the flow rate in cu. ft./s. Find the flow rate Q if L=4 ft and the wate head is 0.9 ft.

>> L=4;%堰開口寬度（呎）

>> H=0.9;%堰口溢流水頭高度（呎）

>> Q=3.33*(L-0.2*H)^(3/2);%Q流量（立方呎╱秒）

>> Q

Q =24.8622